1. Technical Field
The present invention relates generally to tire racks and, more particularly to tire racks that are used to store and transport unvulcanized or "green" tires. Specifically, the present invention relates to a green tire rack that supports the upper and lower portions of each green tire with pairs of arcuate plates that are, in turn, supported on dampers that dampen potentially damaging oscillation forces.
2. Background Information
There is a need during the tire manufacturing process to store and transport green tires before they are cured. The racks that are currently used in the art allow the green tires to be automatically transferred to the storage rack from the tire assembly machines. One type of known green tire rack simply employs a pair of horizontal, parallel, side-by-side pins that are configured to fit within the interior of the tire and engage the bead rings such that the green tire rests on the two pins. The pins are long enough to allow up to three green tires to be received next to each other on the pins. The pins are spaced apart so that an automated transfer mechanism can pass between the pins to place the green tires on the rack.
One problem with this known rack is that the tires hanging on the pins are only supported by the point contacts between the bead rings and the pins. Further, the pin rack does not support the green tire from below. The green tires thus tend to sag under their own weight causing the bead rings and the tire to deform. Such deformity leads to nonuniform tires. It is thus desired in the art to provide a green tire rack that supports the green tires in a manner that prevents the green tires from sagging under their own weight.
The green tires are typically transported from one location in the tire assembly plant to another location where the green tires are cured. The transfer frequently occurs with the tires on the pin racks. It is desired to move the pin racks from one location in the plant to the other location as fast as possible to increase the speed the tire manufacturing process. The racks are thus transported through the plant at relatively high speeds with the green tires experiencing various forces as the tire racks hit bumps, speed up, and slow down along the way. These forces cause oscillations to occur in the green tires that can lead to nonuniform cured tires. It is thus desired in the art to provide a green tire rack that prevents such oscillations by dampening the forces experienced by the green tires.
One supporting device capable of supporting green tires that does not employ the two spaced pins discussed above is disclosed in U.S. Pat. No. 3,759,394. The supporting device disclosed in this patent includes a pair of opposed end pieces and a cross bar with one of the end pieces being fixed with respect to the cross bar and the other of the end pieces slidably disposed on the cross bar. The end pieces are interconnected by a plurality of deformable resilient support members that flex outwardly when the one end piece is moved towards the other end piece along the cross bar. The supporting device is used by pulling the end pieces away from each other and inserting the device in the middle of a green tire. The movable end piece is then pushed toward the other end piece causing the resilient members to flex outwardly and fill the interior of the green tire between the tire sidewalls and the tire tread. The movable end piece is then locked in place to maintain the position and configuration of the support device.
U.S. Pat. No. 3,812,974 discloses another green tire support device. The device disclosed in this patent includes a frame that supports a plurality of flexible slings that each carries a green tire. One portion the support frame that carries the sling is capable of pivoting downwardly so that the green tire may be rolled from the rack onto the floor. Although this rack provides a device that supports the tire over a substantial portion of its lower surface area, the rack does not disclose any means for supporting the tires from within and does not disclose a rack that dampens oscillatory forces.
U.S. Pat. No. 3,935,948 discloses a portable storage rack for unvulcanized pneumatic tires. The storage rack includes a plurality of prongs that extend from a base. Each prong carries a curved cradle designed to fit within a green tire between the tire sidewalls. The patent does not disclose a device that supports the tires from below to prevent sagging or one that dampens oscillatory forces.
In view of the foregoing, it is desired in the art to provide a portable storage rack for green tires capable of supporting multiple tires in a manner that prevents each tire from sagging while also providing dampeners that minimize harmful oscillatory forces.